The present invention relates generally to client-server systems and more particularly to clustered data content servers in a network.
In a clustered data server environment, each server stores its contents in a local disk drive. For example, a data server may be a web server, a document server, an image server, a video server, and so on. Each local disk drive is a mirror of an original (or master) disk drive. An authoring server creates and updates web contents in the master disk. New content or updated content are transferred from the authoring server to each web server via a network. If the number of such transfers is too high and/or the size of the data being transferred is too large, it will take a long time to transfer the data. This increases the CPU load of the receiving web server, so that the web server cannot handle incoming HTTP requests while its contents are being updated. For this reason, content update from the authoring server typically cannot occur during the daytime. The problem is exacerbated because Internet traffic is worldwide and it is always “daytime” somewhere in the world.
On the other hand, if a shared file system is implemented, other problems occur. In a shared file system, all of the web servers share a disk drive (more typically a system of disk drives) and a file server manages the meta-data of a file system. However, the file server of this shared file system then becomes the bottleneck, both in terms of reliability and performance. No web server can read the contents from the shared disk drive without the file server and all web servers must communicate with the file server every time there is an attempt to open a file. Consequently, this results in a large latency period which is usually not tolerated by the end-user for any length of time.
There is a need for a solution that can allow real-time updating of a data server's contents. It is desirable to be able to provide this capability especially when the data server is handling client requests. It is desirable to provide real-time content updating without degrading system performance.